As semiconductor devices have become highly integrated, the wiring of circuits has become finer and the inter-wiring distance is also becoming smaller. In a manufacturing field of semiconductor devices, many kinds of materials in the form of films are repetitively formed on a silicon wafer to form a laminated structure. A technique for planarizing the surfaces of wafers has been an important technique to form such a laminated structure, and a polishing apparatus for performing chemical mechanical polishing (CMP) (which is also called as a chemical mechanical polishing apparatus) has been widely used as one means for planarizing the surfaces of wafers as described above.
A conventional CMP apparatus is provided with a linear transporter for transporting a substrate such as a semiconductor wafer along a predetermined transport passage, and a transmission type sensor for detecting the presence or absence of a wafer is provided to each transport stage of the linear transporter. The conventional CMP apparatus is capable of detecting the presence or absence of the wafer on each transport stage by using this sensor.
It is conceivable for the conventional CMP apparatus that the presence or absence of a wafer in the transport passage is checked by using position information of the wafer in the transport passage (information representing a transport stage on which the wafer must be located). For example, when position information of a wafer in the transport passage is inconsistent with a detection result of the sensor, that is, when the detection result of the sensor indicates the absence of a wafer, whereas the sensor should determine the presence of a wafer according to wafer position information, or when the detection result of the sensor indicates “the presence of a wafer”, whereas the sensor should determine the absence of a wafer according to wafer position information, it is conceivable that an alarm is raised to emergently stop the transportation of the wafer.
In some circumstances, the CMP apparatus is provided with a shower nozzle for spraying water (pure water) to a wafer so as to prevent drying of the wafer while the wafer is transported along the transport passage. Furthermore, in some circumstances, water (pure water) is used to wash wafers after polishing. A transmission type sensor (for example, an optical sensor) has a risk of chattering that may be induced in light amount by an effect of such water or sneaking of light, so that misdetection caused by the chattering occurs. For example, the absence of a wafer may be misdetected due to the effect of chattering although a wafer is present, or the presence of a wafer may be misdetected due to the effect of chattering although a wafer is absent.
When such misdetection caused by chattering occurs in the sensor, a determination result as to whether the position information of a wafer in the transport passage and the detection result of the sensor are consistent with each other provides an erroneous determination, so that an alarm is erroneously raised. When the transport of wafers is emergently stopped every time an alarm is erroneously raised as described above, the productivity and through-put of CMP apparatuses are lowered. Therefore, it has been desired to develop a technique capable of reducing the influence of misdetection of a sensor caused by chattering to suppress reduction of the through-put.
An object of the present technique, which has been implemented in view of the foregoing problem, is to provide a substrate processing apparatus capable of reducing the influence of misdetection of a sensor caused by chattering and suppressing reduction of the through-put.
A substrate processing apparatus according to the present technique comprises a transport mechanism that transports a substrate along a predetermined transport passage while holding the substrate, a sensor that detects whether the substrate is held by the transport mechanism, a sensor controller that controls the sensor, a position information acquiring part that acquires position information of the substrate in the transport passage, a detection result acquiring part that acquires a detection result from the sensor, and a determination processor that determines whether the detection result of the sensor is consistent with the position information, wherein when it is determined that the detection result of the sensor is inconsistent with the position information, the sensor controller makes the sensor retry to detect whether the substrate is held.
A substrate presence or absence checking method according to the present technique is a substrate presence or absence checking method to be executed by a substrate processing apparatus including a transport mechanism for transporting a substrate along a predetermined transport passage while holding the substrate, and a sensor for detecting whether the substrate is held by the transport mechanism, and the substrate presence or absence checking method comprises a step for acquiring position information of the substrate in the transport passage; a step for acquiring a detection result from the sensor, a step for determining whether the detection result of the sensor is consistent with the position information, and a step for making the sensor retry to detect whether the substrate is held when it is determined that the detection result of the sensor is inconsistent with the position information.
A program according to the present technique is a program to be executed by a substrate processing apparatus including a transport mechanism for transporting a substrate along a predetermined transport passage while holding the substrate, and a sensor for detecting whether the substrate is held by the transport mechanism, and makes the substrate processing apparatus execute processing of acquiring position information of the substrate in the transport passage, processing of acquiring a detection result from the sensor, processing of determining whether the detection result of the sensor is consistent with the position information, and processing of making the sensor retry to detect whether the substrate is held when it is determined that the detection result of the sensor is inconsistent with the position information.